Feeling electric current on MacBook Pro M1 with charger plugged in

It seems that the UK version of the Macbook Pro M1 is no longer delivered with a properly grounded extension cable with the charger, but rather with a small UK plug directly connected to the charging block. However, that plug is not grounded.

As a result I'm experiencing an extreme unpleasant electric tingling when touching the Macbook Pro when the charger is connected. It is really an annoying sensation. Considering the price of Euro 3000 for this top of the line product, I find it amazing that Apple saved at this vital point of electric safety.

I have attached the image of the plug coming with the box (bottom) and next to it (above) a wire from an older touch bar model. The latter clearly shows the grounding pins, which are missing in the plug. When using the extension from the older Macbook, the electric current is gone. So it is clearly the missing grounding causing the sensation of electric current on the casing.

Tomorrow I will visit the Apple store, let's see what they have to say. I will update the posting accordingly.

I'm seriously not impressed.

Posted on Aug 10, 2023 3:02 PM

Top-ranking reply

landscape_artist

Level 1

26 points

Posted on Feb 21, 2024 4:28 AM

The "tingly" sensation of touching the case of the MacBook is totally normal.

Please note, it is uncomfortable, but not dangerous.

As the power supply is double isolated and the ground of the power supply (the power return wire) is connected to the chassis - it is inevitable that some parasitic voltage will appear on the chassis at around half the supply voltage (60V USA, 120V UK, 110V EUR) - this is the reason why many commenters here don't notice it - they are US/Canada users.

If you look at how a switched mode power supply works, you'll see a there is a essentially a high frequency switch driving a transformer (transformer efficiency varies with frequency and size) and this causes a lot of interference, to get rid of this interference a filter (a capacitor) is connected to "ground" to remove it. However, with a double insulated device, there is no actual "ground" so the chassis has this parasitic voltage sitting on it, the current is microamperes, hence not dangerous.

So, yes, it is very annoying but it is easy to solve, buy an Apple extension cord, it has the ground pin connected and solves the problem entirely. I would dearly like to know why the ground pin isn't connected on the supplied adapter?

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Feeling electric current on MacBook Pro M1 with charger plugged in

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